2/10/2015. Experiences and opportunities in the use of dried blood spot specimens in resource limited settings. Presentation

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1 Presentation Experiences and opportunities in the use of dried blood spot specimens in resource limited settings Why Dried Blood Spots? Screening newborns / childbearing women (EID) Needle Exchange Surveillance ANSPS Future opportunities Philip Cunningham NSW State Reference Laboratory for HIV St Vincent s Hospital Sydney Australia Dried blood spot (DBS) Widely used in early infant HIV diagnosis Applicable to hard-to-reach and remote settings Dried samples are stable at room temperature Simple transport via post possible Self-collection possible Conventional lab possible Seroprevalence surveys for HIV/HCV - ANSPS McLaws ML etal. Prevalence of maternal HIV infection based on anonymous of neonates, Sydney 989. MJA 990 Oct ;53(7): Comparison of plasma and DBS Feature Plasma DBS Requires venipuncture Yes No Requires centrifugation Yes No Stable at "room temperature" No Yes* Biohazard for shipping purposes Yes No Dry ice required for shipping Yes No* HIV DNA PCR (EID) No Yes* HIV RNA virus load Yes Not routine HIV drug resistance (GART) Yes Yes* Volume range -5 ml ml * if kept dry, for at least 2 weeks Day/Month/Year Footnote to go here Page 3 Challenges in resource limited settings Transport and Logistics Laboratory Capacity Debrework Zewdie: 4 th IAS Conference 2007 Plenary: MOPL Health System Capacity Day/Month/Year Footnote to go here Page 5

2 Common failures in regional laboratories Clinical Care Lack of Infrastructure environment Lack of sustainable transport referral pathways Lack of or inadequate training Lack of proficiency Inconsistent availability of supplies, poor quality, inappropriate test kits Failures in management support Data transmission Receipt & review Result Reporting Patient Testing Sample collection Receipt and entry Referral and transport Laboratory The cycle Development of a DBS collection SOP Early infant diagnosis HIV nucleic 2

3 Elution Plate Typical EIA Assay Procedure for Dried Blood Spots Punch 3 or 6 mm disks into microwell plate Assay Plate 4d 48h HIV infection reasonably excluded in non-breast fed infant if negative in 2 or more ( month and 4months) -2mo 3-6mo 6-2mo >2 Negative HIV Ab tests (<month apart) Loss HIV Ab/ Neg DNA = un-infected Infant still Ab Pos at 2mo retest 5-8mo >5-8m Months post partum Add Kit Diluent (50 ul, :30) 2. Cover plate, incubate overnight at 4 o C 3. Shake plate gently to mix 4. Add Diluent to assay plate (25 ul) 5. Transfer DBS eluate (25 ul) to assay plate (:50 final serum dilution). Cover plate, incubate plate 90 min at 37 o C 2. Wash plate 4x 3. Add IgG-Enzyme Conjugate 4. Cover plate, incubate 30 min at 37 o C 5. Add Substrate (50 ul) 6. Incubate 0 min at 25 o C 7. Add Stop Solution (50 ul) 8. Read plate at 405 nm Positive 48h (likely intrauterine Infection - early) Positive 4d (likely intrapartum Infection - late)? consider stop prophylaxis Anti-HIV Positive >8m = HIV infection HIV DNA in the infant blood 3

4 DBS and surveillance - ANSPS Opportunities ANSPS conducted annually since 995 and NSP attendees have participated on ~40,000 occasions. Majority of primary NSP services in Australia participate in the ANSPS. Serological surveillance using DBS (HIV and HCV) serology 203 HCV RNA PCR pilot Monitor blood borne viral infections and associated risk behaviour in PWID Conventional HIV antibody laboratory tests possible Full confirmation by western blot possible HIV DNA/RNA detection possible Window period same as lab Access to hard-to-reach or remote groups Personalizes the sample collection no immediate test result May appeal to people not wanting to engage with health provider / community settings May appeal to other priority populations? Alternative to venous blood confirmation for PoCT reactives? TGA approved are available for patient monitoring HIV viral tests load possible HIV genotypic resistance (RNA >,000 cpy) possible Day/Month/Year Footnote to go here Page 20 DBS and HIV viral load assays 7 Non-Plasma Sample Types NHP BMK URN CSF DBS CXS NHP2 SEM2 Emerging technologies for DBS Expected A Loftis, R Kshatriya, K McCall-Culbreath, S Fiscus and J Nelson. IAS 2009 Day/Month/Year Footnote to go here Page 22 WHO HIVResNet global resistance Potential considerations Regulatory few approved tests make DBS sample claims How are DBS collection kits distributed? Non-return rates may be costly (wasted kits)? DBS not a familiar venous specimen Labs not familiar or set up for DBS processing and Turn around time for results (batched)? Separates HIV from other STI tests eg bacterial STI and syphilis? Loss to follow up? Day/Month/Year Footnote to go here Page 24 4

5 Costs Active projects DBS collection kit ~ $5.00 Australia Post pre-paid envelope for DBS return ~ $5.46 Processing and by conventional lab test - $2.00 Supplemental HIV for DBS: HIV western blot $70 HIV DNA/RNA PCR = $50 HIV DBS included in clinical trials NSW HIV Strategy - new means to improve uptake PNG and Western Pacific EID and confirmatory Indonesia HIV DR country threshold survey for HIV drug resistance and test and treat implementation research HCV simplified monitoring pre and post Rx Day/Month/Year Footnote to go here Page 25 5